If you want to install a different security program on your Windows 10 computer, you'll have to disable Windows Defender. This is because you cannot have more than one antivirus program installed and running at the same time.

Trying to have two security programs running can result in them both seeing each other as threat. This can then grind your computer to a halt as a result.

Only replace Defender with a solid security suite. Read our Which? reviews of the best antivirus software.

How to switch off Defender

To switch Defender protection off, search defender in the Windows 10 search bar, then click the Windows Defender link.

In the window that opens, click Settings. Under Real-time protection, switch the slider to the off position.

Next, install your new software – try not to leave it too long, as your PC will be unprotected until installation is complete.